A recent analysis of lighter rock fragments from the Gale Crater of Mars points to greater similarities with rocks found on Earth. The ChemCam instrument on the Mars Curiosity Rover discovered lighter rocks with the composition of the continental crust.
The ChemCam relies on a laser that vaporizes particles in order for the spectrograph to examine the chemical composition of minerals and microstructures. The spectrograph can accurately analyze particles smaller than 1 millimeter, that is particles that are 10 times smaller than what can be seen on camera.
French and US scientists have analyzed images and the chemical makeup of 22 such rock fragments. They discovered that these light-colored magmatic rocks contain a high amount of feldspar and some traces of quartz, which makes them extremely similar to TTG (Tonalite-Trondjemite-Granodiorite). TTG is a type of rock of a granitic composition indigenous to Earth, that can be found here since the Archean era 2,5 billion years ago.
Roger Wiens, the lead scientist on the ChemCam instrument from Los Alamos National Laboratory, explains the similarities of these lighter rocks with the ones that are found in Earth’s crust: “Along the rover’s path we have seen some beautiful rocks with large, bright crystals, quite unexpected on Mars. As a general rule, light-colored crystals are lower density, and these are abundant in igneous rocks that make up the Earth’s continents.”
The Gale crater, where the Curiosity Rover landed, was formed approximatively 3,7 billion years ago and contains traces of even older rocks. It presents a cut of around 2 miles down into the crust. That provides a great opportunity to look into the forming process of the planet and discover the common points with the forming process of our planet.
The information gathered by the Curiosity Rover is of vital importance because such information could not have been observed externally by the satellites that orbit the planet.
There is a great difference between the newly analyzed rocks and the basaltic rocks we have long believed make up for Mars’ geological composition. So far we believed that Mars is predominantly made of rocks like the ones that form Earth’s oceanic crust.
This discovery confirms that Mars has a primitive crust very similar to Earth’s and such, that the similarities between the Red Planet and ours are greater than we believed them to be. The analysis of these rock fragments led us one step further into understanding the development of the Red Planet and its geological composition.
Photo credits: IBC World